In recent years, numerous alternatives to coal, oil, and natural gas for generating electrical energy have been proposed. Among these alternative sources of energy, the conversion of solar energy to electric energy using photovoltaic solar cells is considered the most promising. However, the current photovoltaic technology comprises limitations that make it difficult to compete with the fossil-fuel technology. In addition to the high costs of semiconductor materials, fabrication and handling, the maximum efficiency of energy conversion that can be achieved by the current photovoltaic technology is about 25%.